The PIO(4) on the serial bluetooth module has been connected to High level (3.3V) for hardware setting. So toggling the switch on the board to ‘M’ end set the module to the master mode, ‘S’ is for slave mode.

The PIO(4) on the Bluetooth Bee module is impening for software setting. Use the AT command AT+role for setting maste/slave mode.

State instructions LED

Example

The Bluetooth module as the master is connected to a USB to ttl converter, the Bluetooth bee as the slave module is stacked on the Bee socket on the V5 expansion shield. The computer send a character ‘a’ via usb to ttl module . After the Arduino have received it via wireless serial communication, it will flash the led on-board and send back a string ‘geeetech’.